If the righteous are not spiritually alive in heaven then from where did the spirits of Moses and Elijah come from at the transfiguration?

According to the author of this article who is from White Throne Ministries, he teaches that the spirits of the dead are not in heaven but sleep in the sands awaiting one of the two resurrections. He quotes the following verse which was written by Peter under the influence of The Holy Spirit. *Acts 2:29* >"2:29 Men and brethren, let me freely speak unto you of the patriarch David, that he is both dead and buried, and his sepulchre is with us unto this day. *Acts 2:34* >For David is not ascended into the heavens:" Jesus talked of a **separation of believers and non-believers at death** through the parable of the rich man and Lazarus and reinforced that teaching on the cross when He told him that he will be with him in paradise that same Friday. *Luke 23:43* >Jesus said to him, “I tell you the truth, today you will be with me in paradise He then says that a different meaning would be conveyed if that comma were to be removed and also that from other events that happened on that Friday we learn that Jesus did not go to paradise on that Friday because of the words Jesus said to Mary after rising from the dead. *John 20:17* >Jesus saith to her, Touch me not: for I have not yet ascended to my Father: According to that author, the words above prove that Jesus did not go to paradise on that Friday, hence justifying the need for a comma in the promise to thief verse. He backs it all up with all the verses from Acts that none of the Fathers have ascended to heaven but my question is, The Book of Revelation says there are martyrs under the altar who cry out to God for revenge against the inhabitants of the earth. These are the spirits of those martyrs that are spiritually in heaven. *Revelation 6:10* >the souls of martyrs who were killed for their faith in God cry out from under the altar, asking God when he will judge and avenge their deaths: The verse above is the first proof that the saints spiritually unite with God in paradise but their flesh await a re-union in the resurrection. The second proof is the presence of Elijah and Moses during the transfiguration for we know Moses died and the angels buried him, Elijah went to heaven with a chariot of fire. Where did their spirits come from during the transfiguration if the spirits of the righteous do not inherit paradise after death?